Applicants claim-priority under 35 U.S.C. xc2xa7119 of German Application No. 199 02 008.6 filed Jan. 21, 1999. Applicants also claim priority under 35 U.S.C. xc2xa7120 of PCT/DE99/04065 filed Dec. 22, 1999. The international application under PCT article 21(2) was not published in English.
The invention relates to an arrangement for the interferometric radar measurement based on the ROSAR principle, as defined in the introductory part of claim 1.
A radar method comprising a synthetic aperture based on rotating antennas (ROSAR) is known from DE 39 22 086.
A method for the interferometric radar measurement in conjunction with a helicopter radar system (Heli-Radar) operating according to the ROSAR principle is been made known by the application firm in DE 199 02 007, which holds the same position in time as the present application. Said method permits a quasi-three-dimensional representation of the radar image of terrain or other obstructions. The invention described in the following is based on said method.
A method for interferometric radar measurements with a synthetic aperture is admittedly known from GRIFFITHS, H., xe2x80x9cInterferometric Synthetic Aperture Radarxe2x80x9d, Electronics and Communication Engineering Journal, GB, Institution of Electrical Engineers, London, Volume 7, No. 6, Dec. 1, 1995 (12-01-1995), pages 247 to 256, XP000545120; ISSN: 0954-0695). Said method, however, requires a radar platform that moves along a substantially linear track. A possibility for such radar measurements without a radar platform moving on its own cannot be realized in conjunction with said method. Furthermore, the corresponding processing algorithms of said method have to be adapted to the linear movement as well. The movement of the antenna is in this way given in a Cartesian system of coordinates. However, contrary to said method, in conjunction with the ROSAR method, processing algorithms are preset in a polar system of coordinates in accordance with the rotational motion of the antennas. This means that it is not possible to apply the processing algorithms of said prior art to ROSAR-systems.
The problem, is solved with an arrangement for interferometric radar measurement having one coherent transmitting antenna for emitting a radar signal, and two coherent receiving antennas that receive a radar signal. The two conerent receiving antennas each have a receiving channel. The antennas are disposed on the Brotating arm of a rotating device. The difference in radar signal path distance between the two coherent receiving antennas and the measured points of impact is then calculated using the wavelength xcex of said emitted radar signal and the measured phase of the receiving echo of the two coherent receiving channels. The arrangement is embodied as an interferometric ROSAR system, and positioned in such a way that each relevant area of the field to be measured can be detected. To obtain an image of the overall situation, ROSAR systems can form a data network when linked together.
Said problem is solved with the help of the measures specified in claim 1. Embodiments and advanced developments of the invention are specified in the dependent claims and explained in greater detail in the following description with the help of an exemplified embodiment. Said explanations are supplemented by the figures of the drawing, in which: